Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 22
Filtrar
Mais filtros








Base de dados
Intervalo de ano de publicação
1.
Talanta ; 281: 126811, 2025 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-39241647

RESUMO

The analysis of per- and polyfluoroalkyl substances (PFAS) via sum parameters like extractable organic fluorine (EOF) in combination with high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) is highly promising regarding fluorine sensitivity and selectivity. However, the HR-CS-GFMAS method includes several drying and heating steps which can lead to losses of volatile PFAS before the molecular formation step using e.g., GaF formation. Hence, the method leads to a strong discrimination of PFAS within the EOF depending on their physical/chemical properties and is therefore associated with reduced accuracy. To reduce this discrepancy and to indicate realistic PFAS pollution values, an optimization of the HR-CS-GFMAS method for PFAS analysis is needed. Hence, we determined fluorine response factors of several PFAS with different physical/chemical properties upon application of systematic optimization steps. We could therefore improve the method's sensitivity for PFAS analysis using a modifier drying pre-treatment step followed by a sequential injection of sample solutions. The highest improvement in sensitivity of volatile PFAS was shown upon addition of a Mg modifier during drying pre-treatment. Thereby, during optimization the relative standard deviation of fluorine response factors could be reduced from 55 % (initial method) to 27 % (optimized method) leading to a more accurate determination of organofluorine sum parameters. The method provides an instrumental LOD and LOQ of ß(F) 1.71 µg/L and 5.13 µg/L, respectively. Further validation aimed to investigate several matrix effects with respect to water matrices. Here, substance-specific behavior was observed. For example, perfluorooctanoic acid (PFOA) which was used as calibrator, showed signal suppressions upon high chloride concentrations (>50 mg/L). Hence, a thorough separation of Cl from analytes during sample preparation is needed for accurate sum parameter analysis.

2.
Anal Bioanal Chem ; 2024 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-39230750

RESUMO

Single-particle inductively coupled plasma-mass spectrometry (sp-ICP-MS) is one of the most powerful tools in the thriving field of nanomaterial analysis. Along the same lines, single-cell ICP-MS (sc-ICP-MS) has become an invaluable tool in the study of the variances of cell populations down to a per-cell basis. Their importance and application fields have been listed numerous times, across various reports and reviews. However, not enough attention has been paid to the immense and ongoing development of the tools that are currently available to the analytical community for the acquisition, and more importantly, the treatment of single-particle and single-cell-related data. Due to the ever-increasing demands of modern research, the efficient and dependable treatment of the data has become more important than ever. In addition, the field of single-particle and single-cell analysis suffers due to a large number of approaches for the generated data-with varying levels of specificity and applicability. As a result, finding the appropriate tool or approach, or even comparing results, can be challenging. This article will attempt to bridge these gaps, by covering the evolution and current state of the tools at the disposal of sp-ICP-MS users.

3.
Cardiovasc Res ; 2024 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-39312445

RESUMO

AIMS: Heart failure and associated cachexia is an unresolved and important problem. This study aimed to determine the factors that contribute to cardiac cachexia in a new model of heart failure in mice that lack the integrated stress response (ISR) induced eIF2α phosphatase, PPP1R15A. METHODS AND RESULTS: Mice were irradiated and reconstituted with bone marrow cells. Mice lacking functional PPP1R15A, exhibited dilated cardiomyopathy and severe weight loss following irradiation, whilst wild-type mice were unaffected. This was associated with increased expression of Gdf15 in the heart and increased levels of GDF15 in circulation. We provide evidence that the blockade of GDF15 activity prevents cachexia and slows the progression of heart failure. We also show the relevance of GDF15 to lean mass and protein intake in patients with heart failure. CONCLUSION: Our data suggest that cardiac stress mediates a GDF15-dependent pathway that drives weight loss and worsens cardiac function. Blockade of GDF15 could constitute a novel therapeutic option to limit cardiac cachexia and improve clinical outcomes in patients with severe systolic heart failure.

4.
Angew Chem Int Ed Engl ; 63(18): e202317058, 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38369613

RESUMO

Multi-principal element alloys (MPEAs) are gaining interest in corrosion and electrocatalysis research due to their electrochemical stability across a broad pH range and the design flexibility they offer. Using the equimolar CrCoNi alloy, we observe significant metal dissolution in a corrosive electrolyte (0.1 M NaCl, pH 2) concurrently with the oxygen evolution reaction (OER) in the transpassive region, despite the absence of hysteresis in polarization curves or other obvious corrosion indicators. We present a characterization scheme to delineate the contribution of OER and alloy dissolution, using scanning electrochemical microscopy (SECM) for OER-onset detection, and quantitative chemical analysis with inductively coupled-mass spectrometry (ICP-MS) and ultraviolet visible light (UV/Vis) spectrometry to elucidate metal dissolution processes. In situ electrochemical atomic force microscopy (EC-AFM) revealed that the transpassive metal dissolution on CrCoNi is dominated by intergranular corrosion. These results have significant implications for the stability of MPEAs in corrosion systems, emphasizing the necessity of analytically determining metal ions released from MPEA electrodes into the electrolyte when evaluating Faradaic efficiencies of OER catalysts. The release of transition metal ions not only reduces the Faradaic efficiency of electrolyzers but may also cause poisoning and degradation of membranes in electrochemical reactors.

5.
Nanoscale ; 15(26): 11268-11279, 2023 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-37345980

RESUMO

This study describes an interlaboratory comparison (ILC) among nine (9) laboratories to evaluate and validate the standard operation procedure (SOP) for single-particle (sp) ICP-TOFMS developed within the context of the Horizon 2020 project ACEnano. The ILC was based on the characterization of two different Pt nanoparticle (NP) suspensions in terms of particle mass, particle number concentration, and isotopic composition. The two Pt NP suspensions were measured using icpTOF instruments (TOFWERK AG, Switzerland). Two Pt NP samples were characterized and mass equivalent spherical sizes (MESSs) of 40.4 ± 7 nm and 58.8 ± 8 nm were obtained, respectively. MESSs showed <16% relative standard deviation (RSD) among all participating labs and <4% RSD after exclusion of the two outliers. A good agreement was achieved between the different participating laboratories regarding particle mass, but the particle number concentration results were more scattered, with <53% RSD among all laboratories, which is consistent with results from previous ILC studies conducted using ICP-MS instrumentation equipped with a sequential mass spectrometer. Additionally, the capabilities of sp-ICP-TOFMS to determine masses on a particle basis are discussed with respect to the potential for particle density determination. Finally, because quasi-simultaneous multi-isotope and multi-element determinations are a strength of ICP-TOFMS instrumentation, the precision and trueness of isotope ratio determinations were assessed. The average of 1000 measured particles yielded a precision of below ±1% for intensity ratios of the most abundant Pt isotopes, i.e.194Pt and 195Pt, while the accuracy of isotope ratios with the lower abundant isotopes was limited by counting statistics.

6.
Sci Total Environ ; 885: 163753, 2023 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-37121317

RESUMO

In this study, we compare analytical methods for PFAS determination-target analysis, non-target screening (NTS), direct total oxidizable precursor assay (dTOPA) and extractable organically bound fluorine (EOF). Therefore, suspended particulate matter (SPM) samples from German rivers at different locations in time series from 2005 to 2020 were analyzed to investigate temporal and spatially resolved trends. In this study 3 PFAS mass balances approaches were utilized: (i) PFAA target vs. PFAS dTOPA, (ii) PFAS target vs. EOF and (iii) PFAS target vs. PFAS dTOPA vs. organofluorines NTS vs. EOF. Mass balance approach (i) revealed high proportions of precursor substances in SPM samples. For the time resolved analysis an increase from 94% (2005) to 97% in 2019 was observable. Also for the spatial resolved analysis precursor proportions were high with >84% at all sampling sites. Mass balance approach (ii) showed that the unidentified EOF (uEOF) fraction increased over time from 82% (2005) to 99% (2019). Furthermore, along the river courses the uEOF increased. In the combined mass balance approach (iii) using 4 different analytical approaches EOF fractions were further unraveled. The EOF pattern was fully explainable at the sampling sites at Saar and Elbe rivers. For the time resolved analysis, an increased proportion of the EOF was now explainable. However, still 27% of the EOF for the time resolved analysis and 25% of the EOF for the spatial resolved analysis remained unknown. Therefore, in a complementary approach, both the EOF and dTOPA reveal unknown gaps in the PFAS mass balance and are valuable contributions to PFAS risk assessment. Further research is needed to identify organofluorines summarized in the EOF parameter.

7.
BMJ Case Rep ; 16(1)2023 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-36593074

RESUMO

Coprophagia or the ingestion of faeces has been associated with medical conditions (seizure disorders, cerebral atrophy and tumours) and psychiatric disorders (mental retardation, alcoholism, depression, obsessive compulsive disorder, schizophrenia, fetishes, delirium and dementia). The case of a woman in her 30s presenting with coprophagia and psychotic symptoms following hypoxic brain injury is reported. The case is discussed and literature is reviewed. We investigate cariprazine, a relatively new atypical antipsychotic for treating coprophagia, associated with psychotic symptoms. Psychiatric evaluation revealed cognitive dysfunction and psychotic symptoms. Physical examination and laboratory evaluation were unremarkable. She was treated with haloperidol resulting in resolution of coprophagia. Attempts at switching to alternative antipsychotics, due to side effects, resulted in recurrence of coprophagia. Subsequent relapses required higher doses of haloperidol for remission of coprophagia and psychotic symptoms. She finally responded to cariprazine. While firm conclusions are not possible from the experience of a single case, we suggest cariprazine may also be a treatment option for coprophagia, particularly in patients with psychotic symptoms.


Assuntos
Antipsicóticos , Lesões Encefálicas , Transtornos Psicóticos , Feminino , Humanos , Haloperidol/uso terapêutico , Coprofagia , Transtornos Psicóticos/complicações , Transtornos Psicóticos/tratamento farmacológico , Antipsicóticos/uso terapêutico
8.
Anal Bioanal Chem ; 415(6): 1195-1204, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36633619

RESUMO

Per- and polyfluoroalkyl substances (PFAS) are emerging organic pollutants and can occur in surface and groundwater. To identify the degree of pollution in surface water with PFAS, often targeted HPLC-ESI-MS/MS has been employed in which commonly 30-40 compounds are analyzed. However, other PFAS and organofluorines remain undetected. We sampled surface water of the river Spree and the Teltow Canal in Berlin, Germany, which are affected by the effluent discharge of wastewater treatment plants. Here, we employed high-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) for measuring extractable organofluorines (EOF) and compared in a mass balance approach the total fluorine to the identified and quantified PFAS from the targeted analysis. The analysis highlights that the EOF are in the range expected for an urban river system (Winchell et al. in Sci Total Environ 774, 2021). However, downstream of an effluent discharge, the EOF increased by one order of magnitude, e.g., 40.3 to 574 ng F L-1, along the Teltow Canal. From our target analytes, mostly short-chained perfluorinated carboxylic acids and sulfonates occur in the water, which however makes up less than 10% of the EOF. The increase in EOF in the Teltow Canal correlates well with the increase of perfluorohexanoic acid (PFHxA), indicating that PFHxA is characteristic for the discharged EOF but not responsible for the increase. Hence, it points to PFHxA precursor discharge. The study highlights that EOF screening using HR-CS-GFMAS is necessary to identify the full scale of pollution with regard to PFAS and other organofluorines such as pharmaceutical compounds from the effluent of WWTPs.

9.
Mar Pollut Bull ; 184: 114208, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36307946

RESUMO

The European Marine Strategy Framework Directive (MSFD) requires good ecological status of the marine environment. This also includes the Wadden Sea located in the southeastern part of the North Sea and its chemical status of sediments. Based on results from campaigns conducted in the 1980s, 32 surface sediment samples were taken in 2014 to check whether the sampling strategy required for characterizing the trace element content in sediments is representative and to determine the degree of pollution and potential changes over the last decades. For this purpose the elemental mass fractions of 42 elements were assessed in the ≤20 µm grain size fraction of the surface sediments. Based on cluster analysis a clear correlation between the element distribution and the geographical location of the sampling locations of the German Wadden Sea could be found. As a result of the principal component analysis, three sub-catchments were significantly separated from each other by the characteristic element distributions in the sediments (Norderney and Weser, Elbe and offshore areas, and North Friesland). With the help of discriminant analysis, the classification was confirmed unambiguously. Small anomalies, such as potentially contaminated sites from WWII, could be identified. This proved that the sampling strategy for sediment characterization with reference to trace elements in the Wadden Sea of the German Bight is representative. The impact of regulation and changes on the overall sediment quality is most evident when looking at the environmentally critical elements such as As, Cd, Hg, and Cr. For these elements the mean mass fractions show a significant reduction over the last three decades. Current sediments feature only slightly elevated mass fractions of Ag, Cd, Ce, Cs, Nd, Pb and Se at some sampling locations.


Assuntos
Metais Pesados , Oligoelementos , Poluentes Químicos da Água , Oligoelementos/análise , Sedimentos Geológicos/química , Monitoramento Ambiental/métodos , Poluentes Químicos da Água/análise , Cádmio/análise , Mar do Norte , Metais Pesados/análise
10.
Cell Host Microbe ; 30(3): 357-372.e11, 2022 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-35182467

RESUMO

The induction of interferon (IFN)-stimulated genes by STATs is a critical host defense mechanism against virus infection. Here, we report that a highly expressed poxvirus protein, 018, inhibits IFN-induced signaling by binding to the SH2 domain of STAT1, thereby preventing the association of STAT1 with an activated IFN receptor. Despite encoding other inhibitors of IFN-induced signaling, a poxvirus mutant lacking 018 was attenuated in mice. The 2.0 Å crystal structure of the 018:STAT1 complex reveals a phosphotyrosine-independent mode of 018 binding to the SH2 domain of STAT1. Moreover, the STAT1-binding motif of 018 shows similarity to the STAT1-binding proteins from Nipah virus, which, similar to 018, block the association of STAT1 with an IFN receptor. Overall, these results uncover a conserved mechanism of STAT1 antagonism that is employed independently by distinct virus families.


Assuntos
Poxviridae , Animais , Interferons/metabolismo , Camundongos , Poxviridae/metabolismo , Fator de Transcrição STAT1/genética , Transdução de Sinais
11.
Chemosphere ; 295: 133922, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35143867

RESUMO

Here, we describe an optimized fast and simple extraction method for the determination of per- and polyfluorinated alkyl substances (PFASs) in soils utilizing high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS). To omit the bias of the solid phase extraction (SPE) step commonly used during the analysis of extractable organically bound fluorine (EOF) we optimized a fast and simple SPE-free extraction method. The developed extraction method consists of a liquid-solid extraction using acidified methanol without any additional SPE. Four extraction steps were representative to determine a high proportion of the EOF (>80% of eight extractions). Comparison of the optimized method with and without an additional SPE clean-up step revealed a drastic underestimation of EOF concentrations using SPE. Differences of up to 94% were observed which were not explainable by coextracted inorganic fluoride. Therefore, not only a more accurate but also a more economic as well as ecologic method (bypassing of unnecessary SPE) was developed. The procedural limit of quantification (LOQ) of the developed method was 10.30 µg/kg which was sufficient for quantifying EOF concentrations in all tested samples. For future PFAS monitoring and potential regulative decisions the herein presented optimized extraction method can offer a valuable contribution.


Assuntos
Fluorocarbonos , Espectrometria de Massas em Tandem , Flúor , Fluorocarbonos/análise , Solo , Extração em Fase Sólida
12.
Nanoscale ; 14(1): 86-98, 2021 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-34897345

RESUMO

Highly transparent CeO2/polycarbonate surfaces were fabricated that prevent adhesion, proliferation, and the spread of bacteria. CeO2 nanoparticles with diameters of 10-15 nm and lengths of 100-200 nm for this application were prepared by oxidizing aqueous dispersions of Ce(OH)3 with H2O2 in the presence of nitrilotriacetic acid (NTA) as the capping agent. The surface-functionalized water-dispersible CeO2 nanorods showed high catalytic activity in the halogenation reactions, which makes them highly efficient functional mimics of haloperoxidases. These enzymes are used in nature to prevent the formation of biofilms through the halogenation of signaling compounds that interfere with bacterial cell-cell communication ("quorum sensing"). Bacteria-repellent CeO2/polycarbonate plates were prepared by dip-coating plasma-treated polycarbonate plates in aqueous CeO2 particle dispersions. The quasi-enzymatic activity of the CeO2 coating was demonstrated using phenol red enzyme assays. The monolayer coating of CeO2 nanorods (1.6 µg cm-2) and the bacteria repellent properties were demonstrated by atomic force microscopy, biofilm assays, and fluorescence measurements. The engineered polymer surfaces have the ability to repel biofilms as green antimicrobials on plastics, where H2O2 is present in humid environments such as automotive parts, greenhouses, or plastic containers for rainwater.


Assuntos
Peróxido de Hidrogênio , Pseudomonas aeruginosa , Biofilmes , Plásticos , Cimento de Policarboxilato
14.
Anal Bioanal Chem ; 413(21): 5279-5289, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34302182

RESUMO

A recently introduced inductively coupled plasma-time-of-flight-mass spectrometer (ICP-ToF-MS) shows enhanced sensitivity compared to previous developments and superior isotope ratio precision compared to other ToF and commonly used single-collector ICP-MS instruments. Following this fact, an improvement for isotope dilution ICP-MS using the new instrumentation has been reported. This study aimed at investigating whether this improvement also meets the requirements of species-specific isotope dilution using GC/ICP-MS, where short transient signals are recorded. The results of the analysis of monomethylmercury (MMHg) of a sediment reference material show that isotope ratio precision of ICP-MS instruments equipped with quadrupole, sector-field, and time-of-flight mass analyzers is similar within a broad range of peak signal-to-noise ratio when analyzing one isotopic system. The procedural limit of quantification (LOQ) for MMHg, expressed as mass fraction of Hg being present as MMHg, w(Hg)MMHg, was similar as well for all investigated instruments and ranged between 0.003 and 0.016 µg/kg. Due to the simultaneous detection capability, the ICP-ToF-MS might, however, be more favorable when several isotopic systems are analyzed within one measurement. In a case study, the GC/ICP-ToF-MS coupling was applied for analysis of MMHg in sediments of Finow Canal, a historic German canal heavily polluted with mercury. Mass fractions between 0.180 and 41 µg/kg (w(Hg)MMHg) for MMHg, and 0.056 and 126 mg/kg (w(Hg)total) for total mercury were found in sediment samples taken from the canal upstream and downstream of a former chemical plant.

15.
Dalton Trans ; 50(19): 6528-6538, 2021 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-34002749

RESUMO

Solid state reactions are slow because the diffusion of atoms or ions through the reactant, intermediate and crystalline product phases is the rate-limiting step. This requires days or even weeks of high temperature treatment, and consumption of large amounts of energy. We employed spark-plasma sintering, an engineering technique that is used for high-speed consolidation of powders with a pulsed electric current passing through the sample to carry out the fluorination of niobium oxide in minute intervals. The approach saves time and large amounts of waste energy. Moreover, it allows the preparation of fluorinated niobium oxides on a gram scale using poly(tetrafluoroethylene) (®Teflon) scrap and without toxic chemicals. The synthesis can be upscaled easily to the kg range with appropriate sintering equipment. Finally, NbO2F and Nb3O7F prepared by spark plasma sintering show significant photoelectrocatalytic (PEC) oxygen evolution from water in terms of photocurrent density and incident photon-to-current efficiency (% IPCE), whereas NbO2F and Nb3O7F prepared by conventional high temperature chemistry show little to no PEC response. Our study is a proof of concept for the quick, clean and energy saving production of valuable photocatalysts from plastic waste.

16.
Adv Mater ; 33(20): e2007434, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33837999

RESUMO

A general method to carry out the fluorination of metal oxides with poly(tetrafluoroethylene) (PTFE, Teflon) waste by spark plasma sintering (SPS) on a minute scale with Teflon is reported. The potential of this new approach is highlighted by the following results. i) The tantalum oxyfluorides Ta3 O7 F and TaO2 F are obtained from plastic scrap without using toxic or caustic chemicals for fluorination. ii) Short reaction times (minutes rather than days) reduce the process time the energy costs by almost three orders of magnitude. iii) The oxyfluorides Ta3 O7 F and TaO2 F are produced in gram amounts of nanoparticles. Their synthesis can be upscaled to the kg range with industrial sintering equipment. iv) SPS processing changes the catalytic properties: while conventionally prepared Ta3 O7 F and TaO2 F show little catalytic activity, SPS-prepared Ta3 O7 F and TaO2 F exhibit high activity for photocatalytic oxygen evolution, reaching photoconversion efficiencies up to 24.7% and applied bias to photoconversion values of 0.86%. This study shows that the materials properties are dictated by the processing which poses new challenges to understand and predict the underlying factors.

17.
Rapid Commun Mass Spectrom ; 35(2): e8953, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32970910

RESUMO

RATIONALE: (Eco-)toxicological effects are mostly derived empirically and are not correlated with metal uptake. Furthermore, if the metal content is determined, mostly bulk analysis of the whole organism population is conducted; thus, biological variability is completely disregarded, and this may lead to misleading results. To overcome this issue, we compared two different solid sampling techniques for the analysis of single organisms. METHODS: In this study, complementary electrothermal vaporization/inductively coupled plasma mass spectrometry (ETV/ICP-MS) ⇔ laser ablation/inductively coupled plasma mass spectrometry (LA/ICP-MS)-based methods for the analysis of individual organisms were developed and the results obtained were compared with the concentrations obtained after digestion and measured using ICP-MS. For this purpose, a common (eco-)toxicological test organism, the mud shrimp Corophium volutator, was selected. As proof-of-concept application, these organisms were incubated with environmentally relevant metals from galvanic anodes, which are often used for protection against metal corrosion in, for example, offshore wind farms. RESULTS: The bulk analysis revealed that large quantities of the incubated elements were detectable. Using the ETV/ICP-MS method, we could identify a high biovariability within the population of organisms tested. Using the LA/ICP-MS method, it could be determined that the large quantities of the elements detected were due to adsorption of the metals and not due to uptake, which correlates well with the absence of (eco-)toxicological effects. CONCLUSIONS: The results obtained imply the efficiency of complementary methods to explain the absence or presence of (eco-)toxicological effects. In particular, methods that allow for single-organism analysis or provide even a spatial resolution support the interpretation of ecotoxicological findings.


Assuntos
Anfípodes/metabolismo , Espectrometria de Massas/métodos , Metais Pesados/análise , Anfípodes/química , Animais , Ecotoxicologia/métodos , Técnicas Eletroquímicas , Metais Pesados/farmacocinética , Temperatura
18.
Chemosphere ; 263: 128040, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33297056

RESUMO

The interaction of microplastics with freshwater biota and their interaction with other stressors is still not very well understood. Therefore, we investigated the ingestion, excretion and toxicity of microplastics in the freshwater gastropod Lymnaea stagnalis. MP ingestion was analyzed as tissues levels in L. stagnalis after 6-96 h of exposure to 5-90 µm spherical polystyrene (PS) microplastics. To understand the excretion, tissue levels were determined after 24 h of exposure followed by a 12 h-7 d depuration period. To assess the toxicity, snails were exposed for 28 d to irregular PS microplastics (<63 µm, 6.4-100,000 particles mL-1), both alone and in combination with copper as additional stressor. To compare the toxicity of natural and synthetic particles, we also included diatomite particles. Microplastics ingestion and excretion significantly depended on the particle size and the exposure/depuration duration. An exposure to irregular PS had no effect on survival, reproduction, energy reserves and oxidative stress. However, we observed slight effects on immune cell phagocytosis. Exposure to microplastics did not exacerbate the reproductive toxicity of copper. In addition, there was no pronounced difference between the effects of microplastics and diatomite. The tolerance towards microplastics may originate from an adaptation of L. stagnalis to particle-rich environments or a general stress resilience. In conclusion, despite high uptake rates, PS fragments do not appear to be a relevant stressor for stress tolerant freshwater gastropods considering current environmental levels of microplastics.


Assuntos
Lymnaea , Poluentes Químicos da Água , Animais , Cobre/toxicidade , Ingestão de Alimentos , Água Doce , Microplásticos , Plásticos/toxicidade , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
19.
Anal Bioanal Chem ; 413(1): 103-115, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33164152

RESUMO

In this study, we compare combustion ion chromatography (CIC) and high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) with respect to their applicability for determining organically bound fluorine sum parameters. Extractable (EOF) and adsorbable (AOF) organically bound fluorine as well as total fluorine (TF) were measured in samples from river Spree in Berlin, Germany, to reveal the advantages and disadvantages of the two techniques used as well as the two established fluorine sum parameters AOF and EOF. TF concentrations determined via HR-CS-GFMAS and CIC were comparable between 148 and 270 µg/L. On average, AOF concentrations were higher than EOF concentrations, with AOF making up 0.14-0.81% of TF (determined using CIC) and EOF 0.04-0.28% of TF (determined using HR-CS-GFMAS). The results obtained by the two independent methods were in good agreement. It turned out that HR-CS-GFMAS is a more sensitive and precise method for fluorine analysis compared to CIC. EOF and AOF are comparable tools in risk evaluation for the emerging pollutants per- and polyfluorinated alkyl substances; however, EOF is much faster to conduct. Graphical abstract.

20.
PLoS One ; 15(7): e0236120, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32687518

RESUMO

The presence of microplastic (MP) particles in aquatic environments raised concern about possible enrichment of organic and inorganic pollutants due to their specific surface and chemical properties. In particular the role of metals within this context is still poorly understood. Therefore, the aim of this work was to develop a fully validated acid digestion protocol for metal analysis in different polymers, which is a prerequisite to study such interactions. The proposed digestion protocol was validated using six different certified reference materials in the microplastic size range consisting of polyethylene, polypropylene, acrylonitrile butadiene styrene and polyvinyl chloride. As ICP-MS/MS enabled time-efficient, sensitive and robust analysis of 56 metals in one measurement, the method was suitable to provide mass fractions for a multitude of other elements beside the certified ones (As, Cd, Cr, Hg, Pb, Sb, Sn and Zn). Three different microwaves, different acid mixtures as well as different temperatures in combination with different hold times were tested for optimization purposes. With the exception of Cr in acrylonitrile butadiene styrene, recovery rates obtained using the optimized protocol for all six certified reference materials fell within a range from 95.9% ± 2.7% to 112% ± 7%. Subsequent optimization further enhanced both precision and recoveries ranging from 103% ± 5% to 107 ± 4% (U; k = 2 (n = 3)) for all certified metals (incl. Cr) in acrylonitrile butadiene styrene. The results clearly show the analytical challenges that come along with metal analysis in chemically resistant plastics. Addressing specific analysis tools for different sorption scenarios and processes as well as the underlying kinetics was beyond this study's scope. However, the future application of the two recommended thoroughly validated total acid digestion protocols as a first step in the direction of harmonization of metal analysis in/on MP will enhance the significance and comparability of the generated data. It will contribute to a better understanding of the role of MP as vector for trace metals in the environment.


Assuntos
Microplásticos/química , Oligoelementos/análise , Incerteza
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA